Surface heater



May l, 1934. F. c, BLAKE 1,956,664

SURFACE HEATER Filed April 5, 1930 2 Sheets-Shea?I l VE/v Tof: @505/004 C. 5M; KE,

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May l, 1934.

F. c. BLAKE 1,956,664

SURFACE HEATER 2 Sheets-Sheet 2 Filed April 5, 1930 Afro/wary.

Patented May 1, 1934 UNITED STATES PATENT oFrlcE 4 Claims.

My invention relates particularly to a device for heating flat surfaces which require controllable heat treatment. One embodiment of the invention is in a self-contained portable unit de- 5 signed to give unusual efficiency in heat-treating asphalt pavements. y

In laying or repairing any type of bituminous pavement such as one composed of an asphaltic composition, which is normally a composition of pulverized stone, sand and asphalt, it is ordinary practice to transport the so-called asphalt from a source of supply to the point of use in a heated and loosely granular state, whereupon it is quickly dumped, levelled out and rolled smooth, while still in a heated and plastic condition.

It is highly desirable in the process of repairing a pavement of the above mentioned type to eliminate joints between the old surface and the newly applied surface. With the useof my surface heater the old surface may be so heated that the material of which the pavement is composed will be softened sufficiently to be raked loose, and then new material can be added. The temperature of the old material is preferably raised to approximately the temperature of the new so that upon rolling, the old and new materials will cohere in such a manner as to bepractically bonded together, thereby prolonging the life of the resurfaced pavement.

It is well known in the art'thata direct flame applied to an asphalt surface is destructive in that the asphaltis burned to the extent that its binding qualities are nearly or totally destroyed. Some diiculty has been experienced in the use of present type surface heaters'through'lack of adequate heat control, in preventing injuriously high temperatures and in preventing the heating fiame from directly contacting the surface under treatment.

It is, therefore, an object of my invention to provide a self-contained portable surface heater including a high temperature or combustion chamber and a delivery chamber, and to provide adjustable means for introducing atomized fuel in such a manner that the combustion of the fuel is completed before reaching the delivery chamber, so that only non-combustible gases or products of combustion of a desired temperature are directed uponthe surface to be treated.

It is another object to provide a surface heater in which both the atomized fuel delivered under pressure and the air delivered for supporting combustion are directed into a cylindrical combustion chamber tangentially, and together set ."3 up a strong whirling action and resulting turbulence which eliminates any stratification of air and gasiiied oil fuel.

It is another object to introduce low pressure air, for supporting combustion of fuel within the combustion chamber of the device in such a manner as to produce a preheating and a whirling action thereof, before it reaches the point where the fuel is injected into the delivery chamber.

It is still another object to provide at suitable locations a plurality of low pressure air ducts to `introduce additional air for supporting combustion of all carbon monoxide gases and for tempering the blast within the delivery chamber.

These and other objects will be apparent from a perusal of the following specification, the acccinpanying drawings, and the appended claims, in which I have shown and described only one complete embodiment of my invention, but it should be understood that I am aware various features thereof may be changed and numerous -embodiments .thereof may be devised without departing from the spirit and scope of my invention. Y

Referring to the drawings:

Fig. l is a side elevation partly in section of my surface heating apparatus.

Fig. 2 is a vertical section taken as indicated by the line 2 2 of Fig. 1.

Figs. 3 and 4 are vertical sections taken as indicated by the lines 3--3 and 4-4 of Fig. 1.

Fig. 5 is a fragmentary horizontal section taken as indicated by the line 5-5 of Fig. 3.

Referring to Fig. 1 of the drawings, I have shown my surface heating device generally designated by the numeral l0. The device has a horizontally extending body portion 11 mounted on a carriage rstructure 12 which includes brackets 13 secured to the body portion 11. These brackets have squared openings 14 therein to receive a squared shaft 15. Revolvably mounted on the outer cylindrical ends 16 of the shaft is a pair of wheels 17. Pivotally secured to a cross bar 18 extending between the brackets 13 is a draw bar 19 which has a coupling member 20 at its outer end forengagement with a mating coupling member on a tractor or other means of locomotion, not shown.

The body portion 11 comprises an outer cylindrical metal shell 21 closed at the forward end 22Y thereof, and provided with an inspection door 23 at the rearward end 24 thereof. The rearward end 24 is provided with a downwardly extending projection Y25. The projection 25 is provided with a central opening 26, which communicates with the interior of the shell 21. The

walls forming the shell 2l are interiorly lined with fire-brick or other refractory material, as indicated at 27. Projecting upwardly into the interior of the shell 2l and adjacent the opening 26 is a bale wall 28, which divides the body 11 into a combustion or furnace chamber 29 and a delivery passage 30. The passage 30 communicates with the chamber 29 through an opening 31 above the baie wall 28, and also communicates at the lower end thereof with the opening 26 in the downwardly extending projection 25.

Positioned below the opening 26 is a pyramidal hood member 32. rlhe hood member 32 has an upwardly extending ange 33, which conforms to the configuration of the downwardly extending projection 25, and is adapted to extend around the projection in slidable relationship therewith. The hood member 32 is supported by cables 34 extending upwardly from brackets 35 to a quadruple winch device 36 operable through a worm gear 37 responsive to a handwheel 38 to raise and lower the hood member relative to the body l1 and a surface 39 therebelow. Coming now to the more pertinent parts of my invention, I show a fuel oil tank 46 mounted on the top of the body 11 at the forward end thereof, as by brackets 41. The tank 40 is provided with a replenishing cap 42 and a fuel delivery pipe 43 having a valve 44. This pipe 43 extends vertically downward adjacent one side of the body 11.

Carried at the forward end of the body l1 on a platform 45 is an air compressor 46 driven from a source of power, not shown, by a shaft 47 through a universal joint 48 which is operably connected to the fly wheel 49 of the compressor 46. The outlet pipe 50 of the compressor 46 is connected to a pressure equalizing tank 51. A delivery pipe 52 of the tank 51 is shown equipped with a valve 53 before terminating in an upwardly extending vertical stand pipe 54, which is axially aligned with the downwardly extending outlet pipe 43 of the fuel oil tank 40.

Pivotally supported between the fuel delivery pipe 43 and the compressed air delivery pipe 54 as by pivotal couplings 55 and 56 is a fuel oil injector 57. Formed in the walls of the body 11 is an injector port 58 which communicates tangentially with the combustion chamber 29. The port 58 is formed so as to extend obliquely relative to the longitudinal axis of the combustion chamber 29 in a rearward direction, as shown best in Fig. 5. The fuel injector 57 is adapted to extend inwardly through the port 58 for the delivery of atomized fuel tangentially into the combustion chamber 29.

Mounted on a platform 59 adjacent the compressor 46 is a fan blower 60 adapted to be driven by a belt and pulley connection 6l with the fly wheel 49 of the compressor 46. Connected to the delivery end of the blower 60 is a manifold 62 adapted to extend longitudinally of the body 11 and closed at the extreme rearward end, as shown at 63 in Fig. 1. Communicating with the manifold 62 are air inlet ducts 64, 65,' and 66 formed in the walls of the body 11. The ducts 64, 65 and 66 likewise communicate tangentially with the combustion chamber 29. Operably positioned relative to each of the ducts 64, 65, and 66 is a damper valve 67 for varying the volume of air delivered through any one of the ducts.

The operation of my invention is as follows:

When it is desired to heat a surface requiring treatment, the hood member 32 is positioned above the desired portion of the surface and lowered relative thereto by manipulation of the handwheel 38 included in the winch device 36.

Assume now that the air compressor 46 and the fan blower 60 are in operation and that the pressure equalizing tank is prepared to deliver air at high pressure to the injector 57 when the valve 53 is opened. The valve 44 is opened, allowing oil fuel to feed by gravity into the injector 57, where, due to the action of the air delivered simultaneously from the tank 51, it is atomized and injected into the combustion chamber 29 at a high velocity. The fuel being directed at an oblique angle into the combustion chamber as well as tangentially relative to the cylindrical walls of the chamber 29 develops a strong centrifugal and spiral or helical whirling action, which not only creates ample turbulence for the complete mixing of oil gases and oxygen bearing air and the elimination of stratification, but also causes the furnace gases to travel rearwardly toward the outlet passage 30 in a long spiral path, somewhat as indicated by dotted lines 79, Fig. 5, in contact with the surface of the re brick lining 27 which is soon heated to such high temperature that it glows or becomes incandescent in the manner characteristic of fire brick and other materials of a similar nature.

It is very important to the invention that the air be introduced tangentially at a velocity which will assist in Vthe turbulence action in the furnace. By this arrangement all c-f the gases in the furnace are travelling tangentially and there is therefore no tendency to carry any fuel from the furnace without its travelling through the circuituous path and in engagement at some time with the heated or glowing walls of the combustion chamber.

Although any number of air ducts may be used to obtain different ranges of eiciency, I ordinan rily prefer to use three, as the ducts 64, 65 and 66. Normally, the duct 64 at the forward end supplies the air for the main combustion of fuel, and is preferably positioned ahead of the injector port 58, as shown in Fig. 5, so that the incoming air is started whirling and is preheated before mixing with the injected fuel. The second duct 65 furnishes excess air to aid the complete combustion of all gases. The third duct 66 situated adjacent the bafe wall 28 and the outlet passage 30 furnishes air to reduce the blast temperature.

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The baiile wall 28, while not essential in the n down the outlet passage 30 into the hood mem- T.

ber 32. The passage of any flame into the passage 30 would indicate to the operator the presence of unburned gases, and the operator by the manipulation of the pivotal injector 57 and the dampers 67 in the ducts 64, 65 and 66, may

obtain the most efiicient setting for proper coordination of iiame action and path of furnace gases.

It will be readily understood from the foregoing description and an inspection of the accompanying drawings that in the use of my invention no difficulty will be experienced in preventing flame from coming in contact with the surface being treated or in maintaining the proper temperature of hot gases being directed upon said surface.

I claim as my invention:

1. In a surface heating device of the type described, the combination of: a body portion; walls forming a combustion chamber within said body portion, said chamber having closed ends, and having a heat delivery passage adjacent one end thereof; adjustable means adjacent the other end of said combustion chamber for injecting atomized fuel tangentially into said chamber to produce a whirling action of the gases Within said chamber; means for introducing air tangentially into said combustion chamber to support combustion therein; means for controlling the inlet of air into said combustion chamber; and a hood associated with said heat delivery passage for directing hot gases from said passage against a surface to be heated.

2. In a surface heating device of the type described, the combination of a body portion; Walls forming a horizontally extending combustion chamber within said body portion, said chamber having closed ends, and having a vertically downwardly extending heat delivery passage adjacent one end thereof, said body portion having a tangential injector port adjacent the other end of said chamber, said port communicating tangentially with said chamber; fuel injecting apparatus adjustably associated with said port, for injecting fuel tangentially into said chamber to cause a whirling action of the gases within said chamber, said body portion and walls provided with a plurality of air inlet ducts communicating tangentially With said chamber; blower means associated with said ducts for introducing air under pressure tangentially into said chamber; and a hood associated with said heat delivery passage for directing hot gases from said passage upon a surface to be heated.

3.r In a surface heating device of the type described, the combination of a body portion; walls forming a horizontally extending combustion chamber Within said body portion, said chamber having closed ends, and having a vertically down- Wardly extending heat delivery passage adjacent one end thereof, said body portion having a tangential injector port kadjacent the other end of said chamber; fuel injecting apparatus adjustably associated with saidport, for injecting fuel tangentially into said chamber to cause a centrifugal and helical motion of the gases within said chamber; an air inlet manifold adjacent said body portion, said body portion and walls provided with la plurality of air inlet ducts extending from said manifold and communicating tangentially with said chamber; blower means associated with said manifold for introducing air under pressure tangentially into said chamber; valves associated with said ducts for controlling the passage of air therethrough; and a hood associated with said heat delivery passage for directing hot gases from said passage upon a surface to be heated.

4. In a surface heating device of the type described, the combination of: a body portion; walls forming a horizontally extending cylindrical combustion chamber within said body portion, said chamber having closed ends, and having a vertically downwardly extending heat delivery passage adjacent one end thereof, said body portion having an injector port adjacent the other end of said chamber, said port communicating tangentially with said chamber; fuel injecting apparatus adjustably associated with said port, for injecting fuel at high pressure tangentially into said chamber to cause a whirling action of the gases within said chamber; low pressure means for introducing air into said chamber to support combustion of the gases therein; and a vertically adjustable hood member associated with said heat delivery passage for directing the hot gases from said passage upon a desired portion of a surface to be heated.

FREDERICK C. BLAKE. 

